Surgical Neurology 64 (2005) S2:106 – S2:108 www.surgicalneurology-online.com Multiple anterior inferior cerebellar artery aneurysms associated with an arteriovenous malformation: case report Mahmut Akyqz, MDT, Recai Tuncer, MD Department of Neurosurgery, Akdeniz University Medical School, Antalya 07070, Turkey Abstract Background: Multiple aneurysms of the proximal part of the anterior inferior cerebellar artery (AICA) associated with a distal arteriovenous malformation (AVM) are extremely rare lesions. Methods: A 52-year-old man was admitted because of sudden headache. Neurological examination revealed ataxia. Computed tomography scan showed a right cerebellar and subarachnoid hemorrhage. Vertebral angiograms demonstrated 3 small aneurysms at the proximal part of the AICA and distal AVM. Results: A right-sided lateral retromastoid suboccipital craniectomy was performed. We observed strangulation and obliteration at the AICA due to multiple clipping for aneurysms. Thus, aneurysms could not be clipped. At 11 years after bleeding, vertebral angiograms showed that 3 aneurysms had slightly enlarged but the AVM remained unchanged. To date, the patient is still doing well except for dizziness. Conclusion: This association is very rare at the AICA level, and definitive treatment of this association is sometimes complex. D 2005 Elsevier Inc. All rights reserved. Keywords: Anterior inferior cerebellar artery; Multiple aneurysms; Arteriovenous malformation 1. Introduction 2. Case description The presence on the same arterial territory of both a saccular aneurysm and an AVM has already been reported, with an incidence ranging from 2.8% to 9.3% [1,9,10]. Although aneurysms of the proximal part of the AICA are very rare lesions, their occurrence in combination with an AVM in the same arterial territory is even more striking. The association of 3 saccular AICA aneurysms with an AVM on the same feeding artery has not been previously reported. In this report, we describe a patient with an extremely rare combination of multiple AICA aneurysms with an AVM. A 52-year-old man was admitted with sudden headache in 1993. Neurological examination revealed ataxia. Computed tomography showed a right cerebellar hemorrhage and SAH. Vertebral angiograms revealed 3 small aneurysms at the proximal part of the right AICA and an AVM distal from the aneurysms (Fig. 1). The AVM was fed by the dilated right AICA and drained into the superior petrosal sinus. We performed a right-sided lateral retromastoid suboccipital craniectomy. The AICA was followed to the periphery until aneurysms could be observed. Three aneurysms and the AVM were identified at the proximal part of the AICA and the distal part of the AICA, respectively. First, aneurysms were clipped, but we observed strangulation and obliteration at the AICA due to multiple clipping for aneurysms, thus we removed the clips. Postoperatively, the patient complained of dizziness and tinnitus. To date, 11 years after bleeding, the patient is still doing well except for dizziness. The patient was followed radiologically and neurologically. Complete 4-vessel Abbreviations: AICA, anterior inferior cerebellar artery; AVM, arteriovenous malformation; SAH, subarachnoid hemorrhage. T Corresponding author. Tel.: +90 242 2274343-66349; fax: +90 242 2274343-66349. E-mail addresses: mahmutakyuz@akdeniz.edu.tr, mahmutakyuz@superonline.com.tr (M. Akyqz). 0090-3019/$ – see front matter D 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2005.07.037 M. Akyüz, R. Tuncer / Surgical Neurology 64 (2005) S2:106 – S2:108 S2:107 angiograms were performed at 5 and 11 years after the bleeding. At 11 years after the bleeding, vertebral angiograms showed that 3 aneurysms had slightly enlarged, but the AVM remained unchanged (Fig. 2). 3. Discussion Anterior inferior cerebellar artery aneurysms are very rare, comprising far less than 1% of all intracranial aneurysms [3]. The occurrence of an intracranial saccular aneurysm of the feeding artery to an AVM is a well-known phenomenon [1,7,9]. The increase in the blood flow in a vessel feeding an AVM predisposes the development of an aneurysm on that feeding vessel. The association of an AICA aneurysm with an AVM on the same feeding artery has been described in 10 other cases [2- 6,8,11]. Spetzler et al [3] reported that 4 patients presented with AVMs and flow-related AICA aneurysms in their series of 34 cases. However, occurrence of multiple saccular aneurysms and an AVM in the location of the AICA has not been previously reported in the literature. The clinical presentation of the proximal AICA aneurysm has generally included a gradual onset of a cerebellopontine angle syndrome or a sudden onset of an SAH. In our case, the onset was that of a typical SAH and intracerebellar hemorrhage due to AVM bleeding. Later, the audiovestibular symptom continued to the present as paroxysmal episodes. The surgical exposure of AICA aneurysms is complex because of the distance of the lesions from the cranial base and their close relationship to the brainstem and lower cranial nerves. Spetzler et al [3] reported a complication rate of almost 60%, indicating the complexity of these lesions. In our case, surgical treatment of multiple aneurysms was not feasible because of strangulation of the AICA. Treatment of AVM alone was not attempted because it might lead to an increased risk for bleeding from the remaining lesions Fig. 2. Vertebral angiogram showing 3 small aneurysms at the AICA that had slightly enlarged at 11 years after bleeding. due to the altered hemodynamic situation. Endovascular therapy is also not recommended for the treatment of AICA aneurysms [3]. The long-term (11 years) follow-up result is important. Although the natural histories of ruptured AVM and unruptured aneurysm are well known, there is no longterm record regarding aneurysm and AVM together in the literature. In conclusion, definitive treatment of the AICA aneurysm associated with an AVM is sometimes complex, especially in multiple aneurysms. Acknowledgment This study was supported by the Akdeniz University Research Foundation. References Fig. 1. Vertebral angiogram at admission showing 3 small aneurysms and a peripheral AVM fed by the AICA and draining into the superior petrosal sinus. [1] Cockroft KM, Thompson RC, Steinberg GK. Aneurysms and arteriovenous malformations. Neurosurg Clin N Am 1998;9:565 - 76. [2] Gacs G, Vinuela F, Fox AJ, et al. Peripheral aneurysm of the cerebellar arteries. Review of 16 cases. J Neurosurg 1983;58:63 - 8. [3] Gonzales LF, Alexander MJ, McDougall CG, et al. Anteroinferior cerebellar artery aneurysms: surgical approaches and outcomes — a review of 34 cases. Neurosurgery 2004;55(5):1025 - 35. [4] Kikuchi K, Kamisato N, Sasanuma J, et al. Trigeminal neuralgia associated with posterior fossa arteriovenous malformation and aneurysm fed by the same artery. 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